Page 31 of the current Mauser catalogue shows a picture of a Zeiss scope being mounted to an M03 using M03 Double Square Mounts! I think that's a good sign.
Yes - the Double Square Mount comes in rail-mount versions to suit Zeiss and Swarovski scope rails (and I think S&B too?). There are also versions for rings and one with a picatinny rail. Here is a link to a Triebel.com page showing the Zeiss variant.
And here's a link to the same product on the Eurooptic.com site - though out of stock.
I'm sure you'll be able to find a Mauser M03 Double Square Mount with Zeiss scope rail fitting if you contact the good dealers. One that sells both Mauser rifles and Zeiss scopes would be a good start - such as Miall's here in Oz.
As you've seen from my M03 blog, I'm using the ring mount versions, with Mauser 30mm rings for three Zeiss scopes and Blaser 34mm rings for one Kahles scope.
Regards, Rick.